Double-stage variable-speed oppositely-rotating axial flow pump flow passage component for water spraying propelling

Abstract

The invention discloses a double-stage variable-speed oppositely-rotating axial flow pump flow passage component for water spraying propelling. A primary-stage impeller is in an inducer mode. The rotating direction of the primary-stage impeller is opposite to the rotating direction of a secondary-stage impeller. The rotating speed of the primary-stage impeller and the rotating speed of the secondary-stage impeller are different so as to meet the cavitation performance requirement and the lift efficiency requirement respectively. The ratio of the rotating speed n1 of the primary-stage impeller to the rotating speed n2 of the secondary-stage impeller is between 1 and 2. The boss diameter ratio dh to D of the primary-stage impeller is between 0.25 and 0.6. According to the double-stage variable-speed oppositely-rotating axial flow pump flow passage component for water spraying propelling, a double-stage variable-speed oppositely-rotating axial flow pump is good in cavitation resistant performance, high in lift efficiency and compact in structure, expands the use range of a traditional axial flow pump, and is applicable to the water spraying propelling fields with the operating requirements of good cavitation resistant performance, high lift efficiency, compact structures and the like.

Description

technical field [0001] The invention belongs to a water jet propulsion device, in particular to a flow-passing part of a pump. Background technique [0002] Usually the axial flow water jet propulsion pump is the most widely used form of water jet propulsion. At present, its design theory and design method mainly refer to the design theory of vane pump, but the operating environment of axial flow water jet propulsion pump is completely different from that of axial flow pump. Due to the needs of high-performance ship operation, the axial-flow water jet propulsion pump requires good anti-cavitation performance, high stability and wide operating range. [0003] So far, the design method of axial flow pumps in my country still follows the design theory of the former Soviet Union, that is, the lift method based on the aerodynamic characteristics of a single airfoil or the arc method based on the 0-thickness airfoil cascade. The so-called lift method is to correct the aerodynam...

AI Technical Summary

Problems solved by technology

[0004] Due to the large thrust required by the axial-flow water jet propulsion pump, the relative flow head is relatively high, and the axial-flow pump is a low-lift pump. The traditional axial-flow pump design has poor anti-cavitation performance, resulting in large noise and vibration. And the impeller will be damaged by corrosion, resulting in a decrease in pump performance

In addition, the high-efficiency zone of the axial flow pump is very narrow, and severe vibration will occur under low flow conditions

Obviously, single-stage or multi-stage axial flow pumps designed by traditional design methods cannot meet the requirements of modern high-performance ships with good anti-cavitation performance, high stability, and wide operating range.

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